Amazonas - The Great Amazon River

According to a National Geographic Society article in 1971, the source of the Amazon is at Mount Mismi, at an elevation of 5,597 meters in the Peruvian region of Arequipa in the Andes.

One of the water springs on the walls of Mount Mismi Photo: Oton Barros/DSR/INPE /Divulgação

Scientists from Peru and Brazil have proven that the Amazon is the world’s largest river, not only in volume of water but also in length. Its exact source was set by the Peruvian National Geographic Institute (IGN) and the Brazilian National Institute of Space Research (INPE).

Undergoing harsh climatic conditions, the expedition reached the top of Mount Mismi, at an elevation above 5,000 meters, and ventured through the deep, steep creek valleys of Carhuasanta and Apacheta, on the slopes of the mountain to complete their work.

“The official results compelled the international scientific community to agree that the Amazon River is the world’s most extensive river”, stated the general director of the Dept. of Cartography of IGN, Ciro Serra, as he recalled that this is already recognized by organizations such as the “National Geographic Society”.

Scientists from the Brazil’s National Space Research Institute (INPE), the Peruvian National Geographic Institute (IGN), the Brazilian National Geographic and Statistics Institute (IBGE), and Brazilian National Water Agency (ANA) took 16 years of surveying and research to retrace the Amazon from its mouth at the boundary between the States of Amapá and Pará, all the way up to its source at the headwaters of the Apurimac River in Peru.

CBERS-2 Sino-Brazilian satellite image of the Lloqueta River & its 2 main creek valleys. Carruahsanta to the right and Apacheta to the left.

The members of the 1st Scientific Expedition for the Source of the Amazon River, formed by scientists from the Peruvian IGN and the Brazilian INPR travelled in 2007 to Mismi and the Carhuasanta and Apacheta creek valleys in search for the source of the Amazon. It took six days and five nights in inhospitable weather at 4,600 meters elevation above sea level for the first Brazilian scientific expedition to determine the location of the source of the Amazon River in the Chila Mountain Chain in the Andes of southern Peru.

After setting geodesic bench marks in the creek valleys which were presumed to be the sources of the Amazon and measuring the flow rates of each one, expedition members concluded that the source of the river was more than 5,000 meters above sea level and that its length was greater than that of the Nile. Those measurements conducted by INPE added another 230 kilometers to the Amazon’s length.

The data collected show that the main slope begins at Nevado Mismi Mt. starting at Apacheta creek. For the entire stretch between the source and the Atlantic Ocean the river course receives the names of Lloqueta, Apurimac, Ene, Tambo, Ucayali, Solimões and Amazon.

According to researcher Paulo Roberto Martini, who coordinated the study, in order to measure the length of the rivers, geoprocessing and Geocover ortho-rectified mosaics were applied. “Data interpretation was done directly on the images by using SPRING, a geoprocessing software developed by INPE”, as announced by INPE in a communication.

The Amazon was discovered by the Spanish conquistador Francisco Orellana in 1542. It is 6,992 kilometers in length, according to these new discoveries; it is followed by the Nile and the Yellow River (Yang Tzé) in China, which are respectively 6,852 and 6,300 kilometers long.

Marco Geodésico instalado na Quebrada Apacheta. Foto: Oton Barros/DSR/INPE/Divulgação

The controversy over the Amazon River has been going on for many years since the beginning of the Spanish colonization. Jesuit priest Cristóbal de Acuña presented his theory about the source of the gigantic river as being in the Andes, in a letter in 1641 to the king of Spain Phillip IV of Hapsburg, called “The Great” and “King of the Planet”.

Spanish navigator Vicente Pizón called the river Fresh Water Sea in the 15th century. Its mouth goes from the Marajó Archipelago in Pará to the coast of Amapá, stretching over an area of 250 kilometers. Its brown, muddy waters penetrate more than 300 kilometers into the blue waters of the ocean, and fertilizing the Atlantic with at least 11% of the planet’s fresh water. This world of fresh water reaches the Caribbean, the Gulf Stream and South Florida in the U.S., where typical Amazonian vegetation can be found – seeds from the Humid Tropics carried by the Fresh Water Ocean to the limits of the Northern Tropics.

It is a colossal brown spine that is the backbone of the largest water basin in the world formed by more than a thousand giant rivers, over an area of 5,846,100 square kilometers in the north of South America bathing Peru, Colombia, Brazil, Bolivia, Ecuador, Venezuela and Guyana. The Negro River alone has more fresh water than all of Europe.

Foto tirada no cume do Nevado Mismi. Foto: Oton Barros/DSR/INPE/Divulgação

The elevation of the waters of the Amazon River varies around 10.55 meters on average and its depth reaches 100 meters. The average flow velocity is 2.5 kilometers per hour, reaching 8 kilometers per hour in Óbidos, Pará, 1,000 kilometers from the sea, where its narrowest point is a gorge 2.6 kilometers wide. The river’s widest point (outside of the Amazon’s mouth) is near the mouth of the Xingu River on its right bank at 20 kilometers wide; but, during the great flooding in the rainy season, it can reach a width of 50 kilometers. The Amazon is navigable for ocean-going ships from its mouth up to the Peruvian town of Iquitos along 3,700 kilometers. Its navigable thalweg is always above 20 meters and reaches 500 near its mouth.

The discharge flow of this sea-like river is always at least 200,000 cubic meters per second. It releases into the Atlantic Ocean 400,000 cubic meters per second on average, and can go up to 600,000 cubic meters. It also discharges 3 million tons of sediments into the Atlantic Ocean on a daily basis.

Source: INPE

Read also

• History, Waterways and Tides
• Ports of the Eastern Amazon